Calculators · rising sign
Rising sign
The degree of the ecliptic climbing over the eastern horizon at the moment you were born. It moves through all twelve signs every day, so this is the one calculation where a remembered time is not good enough.
The time zone is the one your birthplace was on that day, summer time included. Get it wrong by an hour and the ascendant moves by half a sign, which is the largest error any single field on this site can cause.
How this is computed
The ascendant is the point where the ecliptic — the Sun’s annual path, and the line the twelve signs are marked along — crosses the eastern horizon. Because the Earth turns once a day, that point travels the whole zodiac every day, which is why this is the fastest of the three and why the time matters most here.
It is found from three quantities: the local sidereal time, which is where the sky has rotated to at your longitude; the obliquity of the ecliptic, the 23.4° tilt of the Earth’s axis, taken as its true value at your date rather than as a constant; and your latitude, which sets the angle the horizon cuts the sky at.
The signs do not rise at an even two hours each. Near the equator they come close; the further from it you were born, the more the rate varies — some signs taking well under an hour and their opposites taking three or more. The figure above is measured for your actual moment rather than assumed, which is why it is rarely exactly 120 minutes.